A rather wide variety of magnetic pickup tools for retrieving magnetically attractable objects are known which include a somewhat flexible shaft for manipulating a magnet on the end of the shaft into an otherwise inaccessible area. Such tools are often employed in tight places surrounded by metal parts which of course are also magnetically attractable. Therefore, it is often difficult to control the positioning of the magnet on the tool in such situations and particularly so since the flexible shaft causes the magnet to be drawn toward such metal parts.
Various magnetic devices are known for varying the strength of a magnet and include compound magnet systems where the relative orientation of two or more magnets is adjusted to adjust the magnetic force. Additionally, magnetic tools are known where the distance between the magnet and the working face is adjusted to decrease the magnetic force applied at the face. However, these types of devices often do not provide sufficient magnetic force and do not substantially decrease the lateral magnetic attraction toward surrounding magnetically attractable materials. U.S. Pat. No. 4,813,729 discloses a magnetic retrieval tool which is said to overcome the foregoing problems. Additionally, U.S. Pat. No. 512,381 shows a magnetic pickup tool in which the magnet is slidably located in an outer sleeve. Although the tool of this patent does overcome the problem of the magnet being attracted to other unwanted magnetic articles, the shaft of this tool is not flexible and thus severely limits the use of the tool. A somewhat similar arrangement is shown in U.S. Pat. No. 2,471,764 and it appears that the tool of this patent is also subject to the problem of the shaft being totally inflexible. In U.S. Pat. No. 2,683,618 there is also shown an automatic pickup device which provides for shielding of the magnet and also incorporates a somewhat flexible shaft. Interestingly, the tools of these patents are quite complicated in construction and obviously rather costly to make.
Accordingly, it is a principal object of this invention to provide a magnetic pickup tool in which the flexibility of the shaft can be widely varied and in which the magnet which is employed may be moved from an inoperative to an operative position in order to prevent the magnet from being attracted to unwanted metal objects during positioning of the tool. A further object of this invention is to provide a magnetic pickup tool which is simple in construction and of very low cost. These and other objects of the invention will become more apparent as this specification proceeds.